Relay circuit



Feb. 8, 1938. A BUSCH 2,107,746

RELAY CIRCUIT Filqd March 11,l 1956 A i/"30 i i F/G. .l

A TTOR/VEV ,1" for a group busy meter.

Patented Feb. 8, 1938 PATEN'I OFFICE RELAY CIRCUIT Aloysius J. Busch, Bellerose, N. Y., assignor to Bell Telephone Laboratories Incorporated, New York,N. Y., a corporation of New York Application March 11, 1936, Serial No. 68,241

6 Claims.

This invention relates tol telephone systems and has for its object to increase the speed with .Whichr selections take place.

The invention finds one embodiment Vin the '5 cross-bar system where a plurality of elements Yarev ytested simultaneously, by connecting a test relayV toy each element. The relays are arranged to operatewhen the elements to which they are connected are idle. When the relays have opo erated all but one of them is released and the release of these relays immediately indicates the element lselected. If only one relay operates, indicating that the last element of the group has been seized, a circuitjis immediately closed The indicating circuit and the metering circuit'extend over the front contact of one relay and the back contacts of all of the remainingrelays.

For a complete Across-bartelephone system of rwhich the present disclosure is a part, reference is made to the applicationk of W. W. Carpenter,

Serial No. 68,262, llled March 1l, 1936, now Patover the back contacts of that relay and the in ent No. 2,089,921, issued Aug. 10, 1937.

@The invention will be more clearly understood Yfrom a consideration of the following description'y in connection'with the accompanying drawf ing, `in which:

Fig. 1 shows a series of test relays with a circuit for immediate selection; and

Fig.'2 shows a similar group of relays equipped 'with a circuit for operating a meter.y

Y Referring rst to Fig. 1, the group of relays for making selections includes a series, usually of ten relays, to |09,l each relay having two windings, the upper Vwindings Vof these relays Y being connected in multiple to battery over the V`upper back contact of krelay |20. The lower windings of the relays are used for locking the relays and are connected to ground. When it is desiredto make a test, relays |00 to |09 are .l connected simultaneously over conductors ||0 Y to, ||S| to the equipment to be tested, idle equipment being characterized in this case by ground. Assuming vthat the equipment connected to conductor ||0 is idle, ground will be connected over that conductor to the upper winding of relay I 00, back. contact of relay to battery. Relay |00 operates, closing a locking circuit for itselfr from ground through itslower winding and lower front contact,v conductor |40, through the winding of relay |20 and battery. If other relays are connected to idle equipment vthey also will operate but cannot lock since their'locking circuits are opened at the contact of relay |00.

As soon asy the locking Acircuit through`the winding o-f relay |20 is established, that relay operates, disconnecting the operating battery from the remaining relays which immediately release. Relay |20 also closes a circuit from ground over its front contact to the armature of relay |09. Assuming that relay |00 is operated and therefore locked, the circuit closed by relay |20 extends over the back contact of relay |09, outer upper back contact of relay |08, upper back contacts of the intermediate relays and relay Y |0|, inner upper front contact of relay |00, outer upper front contact of relay |00 to conductor |30 to seize the equipment found idle. This circuit is closed immediately that the unlocked relays release but does not become effective as long as more than one relay remains operated. For eX- ample, assume that relay |0| is operated and locked and that relay |09 fails to release because .of a sticky contact, the circuit closed by relay |20 will extend as before to the inner armature of relay |09, over the front contact of that armature to the inner armature of relay |08 and termediate relays to the armature of relay |00 where the circuit would be opened,

'I'he relay chain is arranged to give preference tothe equipment reached over conductor ||0 and thereafter to the equipment reached over conductors H9, H8, etc. However, preference may be given to the equipment reached over conductor by connecting the winding of relay |20 to conductor |l|| instead of to conductor |40 and similarly preference may be given to other equipment by connecting relay |20 to some other one of the conductors |40 to |49.

Referring now to Fig. 2, there is provided a set of ten relays 200 to 209. These relays are single wound relays, one side of each winding extending to ground over a back contact of relay 2|0. The other side of the windings are con- 40 nected over conductors 220 to 229 to equipment which is marked idle by battery through a resistance. This set of relays can be used to test any one of a plurality of groups of circuits and is connected to the desired group by means of relays 2|| and 2|2. When a test is to be made and relay 2||, for example, is operated, assuming that all of the circuits to be tested are idle, a circuit will be closed from battery through resistance 230, inner upper front contact of relay 2||, conductor 220, winding of relay 200, inner upper contact of relay 2|0 to ground. Relay 200 operates closing a circuit from battery at its inner upper front contact through its winding and over its outer lower front contact to ground.

This locking battery is supplied over the contact of a relay (not shown) in order to release the locked-up relays when the equipment as a whole has completed its function. Relay 200 also connects ground over its two lower front contacts to the winding of relay 2|0 and battery. Similar circuits will be closed from resistances 23| to 239 to relays 20| to 209. These relays also look between battery at their inner upper front contacts and ground at their outer lower front contacts, closing parallel circuits for relay 2li).

Relays 2U!) to 209 over armatures which have not been shown control the selection of an idle piece of equipment and initiate its operation, a preference circuit deciding which piece of equipment is to be selected where more than one piece is idle. Assuming that only one piece of equipment is idle, for example that represented by resistance 238, relay 208 is operated in series with resistance 238, locking through the winding of relay 2|0 in the manner above described now Amaking this last piece of idle equipment busy.

Relays 282, 20| and 209 and the remaining relays of the series cannot operate. When relay 2|!! operates it closes a circuit from ground over its front contact, back contact of relay 269, outer upper front contact of relay 268, inner upper back contacts of the intermediate relays and relays 20| and 20d, conductor 240, over the lower front contact of relay 2|| to the winding of meter 24| and battery. Meter 24| records the fact that all of the pieces of equipment tested by this chain of relays over the contacts of relay 2|| have ,become simultaneously busy. If the pieces of equipment reached over the contact of relay 2|2 were being tested the metering circuit would extend over the lower front contact of relay 2 I2 to the winding of meter 242. Therefore, the metering circuit operates the meter individual to the group of equipment being tested at the particular time. If relay 209 were the only relay operated the circuit would extend over the front contact of that relay and the back Contact of the remaining relays. Similarly the circuit is closed whenever only a single relay is operated and all of the remaining relays are normal.

What is claimed is:

1. In a telephone system, a plurality of circuit elements, means for marking these elements as busy or idle, a series of relays, means for connecting said relays to said elements each to each, and means for indicating the presence of an idle element comprising a chain circuit controlled by said relays and including the front contact of a single relay and a back contact of each of the remaining relays.

2. In a telephone system, a series of relays, a chain circuit controlled by said relays including the front contact of a single relay and the back contact of each of the remaining relays, and means to further extend said circuit over an additional front contact of said single relay.

3. In a telephone system, a series of relays, a chain circuit controlled by said relays including the front contact of a single relay and the back contact of each of the remaining relays, means for locking said single relay and means to further extend said circuit over an additional front contact on said single relay.

4. In a telephone system, a series of relays, a chain circuit controlled by said relays including the front contact of a single relay and the back contact of each of the remaining relays, and means whereby said circuit may be used for selectingv purposes whereonly one of said relays may be locked and means for using said circuit to operate a meter when a plurality of said relays may be locked.

5. In a telephone system, a plurality of circuit elements, means for marking these elements as busy or idle and means for selecting an idle element comprising a plurality of relays, means for connecting said relays to said elements each to each, means to operate relays connected to idle elements, means responsive to the operation of any one of said relays to release all but one of said relays, and means immediately responsive to the release of said relays to` indicate the element selected.

6. In a telephone system, a plurality of circuit elements, means for marking these elements as busy or idle, means for selecting an idle element comprising a plurality of relays, means for connecting said relays to said elements each to each, means to operate relays connected to idle elements, and means to operate a meter if only one of said relays becomes operated.

ALOYSIUS J. BUSCH. 

